Apparatus for converting carbonaceous material into fuel gases and the recovery of energy therefrom

ABSTRACT

The invention is concerned with novel apparatus and process for converting crude carbon such as coal, carbonaceous wastes and the like into valuable chemical products and/or energy. A mass of solid crude carbonaceous fuel is fed into a high temperature liquid which acts as a solvent for carbon at a temperature sufficient to carbonize the mass and by which the carbon is separated from impurities. Volatile fractions are removed from the mass which acts as a distillation column. Air, or another oxygen source, is introduced into the reactor wherein it reacts with the carbon dissolved in the liquid therein, which may preferably be iron to form a hot fuel gas. The hot fuel gas is then used to produce useful energy, generally via a stepwise procedure.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is concerned with the conversion of a feed which yieldscarbon on being heated above a carbonization temperature thereof andwhich is solid at ambient temperature, e.g., 20° C., into a hot gas. Thehot gas finds use in energy generation and chemical processing or thelike. Valuable volatile chemicals and impurities may be separated fromthe feed while it is being heated and fed into the reactor wherein thecarbonization and gasification occur.

2. Prior Art

The combustion and gasification of coal and other impure carboncontaining fuels by carbonization and solution of the carbon in molteniron and its oxidation therein is known as a general process. The stateof the prior art in this regard is set out, for example, by J. A.Karnavas, et al, in "ATGAS--Molten Iron Coal Gasification", 1972 AGASynthetic Pipeline Gas Symposium, Chicago, Ill., Oct. 30, 1972, as wellas in Pelczarski, et al, U.S. Pat. Nos. 3,526,478 and 3,533,739.

U.S. Pat. No. 1,838,622 discloses the method and apparatus of a verticaldistillation-pyrolysis chamber linked to a combustion chamber. Somesolids from the vertical chamber enter the combustion chamber and thegaseous products of combustion (non-combustible) directly heat thevertical distillation-pyrolysis chamber. The vertical chamber apparatustreats carbonaceous material, acts as a fractionator, and allows refluxof distillation products. The material proceeds by gravity flow throughthe column, the chamber fractionates volatile components, refluxing isprovided to control the heat distribution within the column, heated gasmay be introduced to heat material within the column, the process iscontinuous, and the column may be characterized as differential.

U.S. Pat. No. 1,759,821 discloses destructive distillation ofcarbonizable material in a retort in which material moves downwardcontinuously and volatile components are fractionated.

U.S. Pat. No. 1,669,023 discloses carbonization and distillation of coalin a vertical chamber. Heat is supplied by upwardly flowing gas and gasmay be added to points along the chamber to regulate the temperaturedistribution.

U.S. Pat. No. 3,109,781 discloses semi-continuous gravity flow ofhydrocarboniferous material through a retort heated by injection of hotnoncombustion-supporting gases at the lower end. Volatile componentsexit at the top end of the retort and enter a fractionator.

U.S. Pat. No. 3,838,015 discloses pyrolytic decomposition of trash inwhich air is admitted at a controlled rate to maintain combustion ofgases produced and therefore regulate the pyrolysis temperature.

U.S. Pat. No. 3,886,048 discloses carbonizing and desulfurizingcarbonaceous material by heating carbonaceous material admixed with ironin a reducing atmosphere and then subjecting the resulting char to anoxidizing atmosphere.

U.S. Pat. No. 2,787,584 discloses continuous carbonization of solidcarbonaceous material by suspending the material in a moving moltenstream at greater than 800° C. An overhead stream of volatized chemicalsand coke which is gravity separated from the molten metal are produced.

U.S. Pat. No. 3,890,908 discloses pyrolytic reduction of carbonaceouswaste material by floating it up through a molten metal bath.

U.S. Pat. No. 1,734,970 discloses flow of carbonaceous material througha molten iron bath to produce volatile and nonvolatile products.

U.S. Pat. No. 2,953,445 discloses a two-chamber molten slag bath reactorfor the production of water gas from a carbonaceous raw material.Gasification of the raw material and carburization of the bath occur inone chamber and combustion occurs in the other. Air or steam may beintroduced into the bath through the walls of the bath or above thesurface level of the bath (in the combustion chamber), the inlet beingarranged tangentially so that the medium is set in circular motionbetween the chambers which are divided by gastight partitions.

Previously mentioned U.S. Pat. No. 3,533,739 discloses combustion ofsulfur-bearing carbonaceous fuel by subsurface injection of the fuel andpreheated air into a molten bath. Sulfur is extracted by the addition oflime and the main product of combustion is carbon monoxide. Carbonmonoxide product may undergo combustion by injection of air. Heatcombustion may be transferred to steam which drives power turbines.

U.S. Pat. No. 1,803,221 discloses apparatus and process for theproduction of hydrogen gas from methane-containing gases in a molteniron bath. The molten iron bath is divided into two parts by a partitionwall which separate gaseous zones but leaves the molten iron free tocirculate. Feed gas is blown in below the surface on one side of thepartition and air is blown in on the other side. (The air may be blownin tangentially so as to cause the iron to circulate).

U.S. Pat. No. 1,592,861 discloses production of water gas by addingcarbonaceous material to a molten bath, passing steam through the bath,maintaining bath circulation to promote absorption of incoming carboninto the bath. U.S. Pat. No. 1,592,860 discloses production of carbonmonoxide by charging iron ore and coal or other fuel into a tower andallowing the mass to rest on the surface of the molten bath (held up bythe buoyant force) followed by absorption of carbon into the bath andmetal reduction.

U.S. Pat. No. 3,084,039 discloses blowing a stream of freeoxygen-containing gas across the surface of a molten iron bathcontaining carbon to produce carbon monoxide gas.

U.S. Pat. No. 314,342 discloses manufacture of hydrogen gas bycontinuous introduction of carbonaceous material, simultaneously withsteam, into a chamber containing a metallic oxide, followed by treatmentof gaseous products with lime.

U.S. Pat. No. 3,933,128 discloses combustion of carbonaceous fueldissolved in a molten salt to produce heat which may be used to generatesteam to drive power turbines.

U.S. Pat. No. 2,876,527 discloses the cracking and dispersion of heavyhydrocarbon feedstocks in molten alkali metal carbonate baths followedby gasification of the dispersed material by contacting with oxygen,steam, or CO₂ at 3000° F. Cracking and combustion occur in separatevessels.

U.S. Pat. No. 3,933,127 discloses a means of sulfur removal fromcarbonaceous fuel during combustion. Fuel, a collector, and oxygen areintroduced into a molten bath of salt. The collector forms a sulfurcompound which is insoluble in molten salt.

U.S. Pat. No. 3,812,620 discloses the cooling of the outer metal shellof a molten metal bath by circulation of fluid through a plurality ofpassages within the shell. A layer of refractory material lies betweenthe bath and the outer metal shell.

SUMMARY OF THE PROBLEM

Because of the increasing scarcity of relatively pure fossil fuels suchas petroleum and natural gas, the use of impure fuels such as coal andwaste materials is rapidly becoming more important. There are basicallythree major considerations which arise in the transition to the use ofthese impure fuels in electric power plants. First, noncombustible andnoxious impurities in the impure fuels must be prevented from beingreleased into the environment after and during combustion. Second,impure fuels generally cannot be used efficiently in high temperatureadvanced energy conversion cycles because of the fouling and corrosioncaused by the high levels of such impurities as fly ash, salt and thelike. Third, impure fuels are much more valuable and useful if they canbe refined into the chemicals and pure fuels they contain instead ofbeing burned completely in their crude form.

While methods are known by which the impurities can be removed from animpure fuel prior to its introduction into a combustor, and othermethods are known whereby impurities can be removed from the flue gasresulting from the combustion of the impure fuel, both of these methodsadd substantially to the cost of the fuel or of the power plant andgenerally degrade the overall efficiency of energy production from thefuel. With respect to refining impure fuels into chemicals it is to benoted that crude petroleum is conventionally refined to obtain thevaluable petrochemicals and fuels it contains before residue therefromis burned in power plants. Coal and wastes are, however, generally notrefined before burning because the gross impurity content makes suchrefining economically infeasible.

The present invention is concerned with an integrated process andapparatus in which impure fuel such as coal, waste products, oil shale,bunker fuel residue, asphalts and the like are continuously refined intovaluable volatile and gaseous fractions which are separated fromnoncombustible and noxious impurities such as ash and sulfur, and theresiduals are combusted to give high temperature gases suitable fordirect use in advanced high-temperature electric power productioncycles. An important advantage of the apparatus and process of thepresent invention is the ability to change the proportions of the outputtherefrom among electric power and the various other valuable products,depending on the relative demand for these products. In this respect,the subject invention provides a capability similar to that of a crudeoil refinery which can change the proportion of automotive fuel,aircraft fuel, heating oils and petrochemicals which it produces fromcrude oil to efficiently meet seasonal fluctuations and demand withminimal inventory and storage facilities. Another significant advantageof the invention is that the problem of efficiently utilizing the hugeamount of char produced in many crude coal refining attempts isinherently avoided since the char is itself consumed and converted intovaluable products and/or energy.

SUMMARY OF THE INVENTION

In one sense the invention is concerned with a process of converting acarbon containing fuel which is solid at ambient temperature into a hotgas. The process comprises introducing a feed which yields carbon onbeing heated above a carbonization temperature thereof and which issolid at ambient temperature, into a carbonization chamber of a reactorand into contact at a temperature above said carbonization temperaturewith a liquid which is a solvent for carbon and which fills said reactorup to a liquid level therein. There is introduced into oxidation chambermeans in said reactor, said oxidation chamber means being separated fromsaid carbonization chamber above said liquid level but being in liquidflow communication therewith below said liquid level, an oxygen source,e.g., oxidizing gas means such as air, other oxygen gas containingmixtures, steam, a metal oxide such as iron oxide, or the like, ormixtures of the preceeding having oxidization ability. The oxygen sourcereacts in an overall exothermic manner with the liquid to elevate thetemperature of the liquid to said temperature above said carbonizationtemperature. Means are provided for forcing convection of the liquidwithin the reactor. A hot gas formed within the oxidation chamber meansis conducted thereawayfrom, said hot gas being formed by reaction of theoxygen.

In another sense, the invention is concerned with a process forconverting a carbon containing feed into a hot gas, comprisingintroducing a feed which yields carbon on being heated above acarbonization temperature thereof and which is solid at ambienttemperature into a reactor having therewithin a liquid solvent forcarbon filling said reactor up to a liquid level therein below a topthereof. The feed introducing comprises contacting a first end of themass of the feed with the liquid, the mass extending linearly into thereactor; progressively adding the feed to a second end of the mass tomaintain the extension thereof into the reactor substantially constantand to create a temperature gradient along the mass; and taking offvolatile fractions of differing volatilities from take-off means spacedfrom one another and arranged to be in gas flow communication withdifferent portions of the mass. Also part of the process is introducinginto the reactor and into contact with the liquid, an oxygen source forreaction with the carbon to produce a sufficient temperature in theliquid to cause carbonization of the first end of the mass and toprovide heat for establishing the temperature gradient.

In other senses yet, the invention comprises particular apparatus forcarrying out the processes as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood by reference to the figures ofthe drawings, wherein like numbers denote like parts throughout andwherein:

FIG. 1 illustrates in a schematic perspective representational view,partially in section, an apparatus and process in accordance with afirst embodiment of the present invention;

FIG. 2 illustrates a side schematic section view, a portion of theapparatus and process of the present invention which relates to a secondembodiment thereof;

FIG. 3 illustrates in side schematic section view a representation of aportion of a third embodiment of the present invention;

FIG. 4 illustrates in side schematic section view, a portion of a fourthembodiment of the apparatus of the present invention;

FIG. 5 illustrates in side schematic sectional view, a fifth embodimentof the present invention;

FIG. 6 illustrates in side schematic section view a variation of FIG. 5;

FIG. 7 illustrates in side schematic section view one form ofcirculation inducing means useful with the apparatus of the presentinvention; and

FIG. 8 illustrates in side schematic section view yet another embodimentof the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

FIG. 1 illustrates an apparatus 10 in accordance with the presentinvention. The apparatus 10 includes a digestor 12, a reactor 14 and anenergy extractor 16.

A feed 18 which yields carbon upon being heated above a carbonizationtemperature thereof and which is solid at ambient temperature is fedinto a top end 20 of the digestor as for example, via a conventionaltransport belt 22. The feed 18 can comprise any of a number of materialsor mixtures thereof. For example the feed can comprise raw coal,undifferentiated industrial and municipal waste, animal and agriculturalwaste, sewage sludge, tar residues, asphalt residues, oil shale, and thelike. The only essential characteristic of the carbon containing fuel isthat it be such that upon being heated to a carbonization temperature ina manner which will be described in following, it is converted intocarbon, and that at ambient or room temperature, e.g., 20° C., it issolid. The term solid is used broadly herein to include glassy solidssuch as tar, asphalt and the like. It should also be noted that the feedcan include non-carbonaceous materials such as scrap iron, limestone orthe like, intermixed therewith and may even advantageously contain oneor more of these materials for reasons which become apparent from thedescription which follows.

The feed 18, after passing into the top end 20 of the digestor 12, thenproceeds downwardly therethrough under the influence of gravity feed.While within the digestor 12, the feed is converted into a generallycontiguous mass 24 because of heat supplied to a bottom end 26 of thedigestor 12 and to a first end 28 of the mass 24. Within the digestor12, a temperature gradient is created in the mass 24 with a highertemperature at the first end 28 thereof and a lower temperature at asecond end 30 thereof. Any volatile components of the feed 18 areprogressively volatilized and, basically, the digestor 12, serves as adistillation and partial thermal cracking column for the feed 18. Aplurality of takeoff means 32 are provided along the length of thedigestor 12 and hence along the length of the mass 24. The highest ofthe takeoff means 32 receives the most volatile gases emitted by themass 24 within the digestor 12, for example, hydrogen, methane and watervapor. The lower of the takeoff means 32 progressively receive highermolecular weight volatizable hydrocarbons produced by distillation,thermal decomposition, and/or cracking, and/or reforming of the feed 18within the mass 24.

Turning now to a consideration of the reactor 14, said reactor 14includes a liquid 34 therewithin which the first end 28 of the mass 24contacts. The liquid 34 is a solvent for carbon and fills the reactor 14up to a liquid level 36 therein, which liquid level 36 is below a top 38of the reactor 14. The reactor 14 preferably includes baffle means 40which completely separate the reactor 14 above the liquid level 36 intoa carbonization chamber 42 and oxidation chamber means 44. The bafflemeans 40 are made to terminate below the liquid level 36 and above abottom 46 of the reactor 14. This allows flow of the liquid 34 betweenthe carbonization chamber 42 and the oxidation chamber means 44. Aplurality of conduits 48 serve as means for introducing oxidizing gasmeans having an oxygen content into the oxidation chamber means 44 andagainst the liquid level 36, generally aimed to cause flow of the liquid34 between the carbonization chamber 42 and the oxidation chamber means44 and thus serves as means for forcing convection of the liquid 34within the reactor 14. Means are also provided for conducting away afirst hot gas from the oxidation chamber means 44. The means forconducting the first hot gas in the embodiment illustrated in FIG. 1comprises a takeoff pipe 52.

Turning particularly to the oxidizing means, it should be noted thatthis oxidizing means should be such that it reacts overall in anexothermic manner with the carbon dissolved in liquid 34 to form carbonmonoxide gas, thus keeping the temperature of the liquid 34 high enoughto remain molten and be above a carbonization temperature of the mass 24of the feed 18. Any number of oxygen containing gases are suitable asthe oxidizing means of the present invention. For example, air isparticularly suitable if it is preheated sufficiently by the exhaustgases or other means to maintain the liquid 34 in the liquid state. Ifthe oxidizing gas has a much higher free oxygen content than air, forexample more than 50%, the reaction is so strongly exothermic that itmay be desirable to mix said gas with steam or to independently addsteam, which itself will oxidize the carbon in the liquid 34 to formcarbon monoxide gas along with hydrogen gas. Since the reaction of steamwith the carbon in the liquid 34 is endothermic, its addition moderatesthe reaction so that it is not overly exothermic and so that the liquid34 remains within the said desirable temperature range. It is alsocontemplated that a metal oxide ore, e.g., iron oxide, can be added tothe liquid 34 wherein it will serve as part or all of the oxidizingmeans and will oxidize the carbon to form carbon monoxide gas and willitself be converted to the metal, e.g., iron, which can be recoveredfrom the reactor 14 within a desirable temperature range, for example,in a range from about 1200° C. to about 1700° C.

The liquid 34 can be any liquid which will serve as a solvent for carbonand which will bind oxygen thereto either by chemical reaction therewithor by significantly dissolving the oxygen therein. For example, theliquid 34 can be a molten carbonate salt or iron or an iron containingalloy. An iron based liquid 34 has been found to be especially desirableand practical for carrying out the various processes of the presentinvention. It should be noted that when the liquid 34 is iron, makeupscrap iron and the like can be added to the digestor 12 along with thefeed 18 to react with and remove impurities such as sulfur from the feedand prevent such impurities from being evolved with the valuable gasesduring the carbonization process. Feed streams such as coal and trashhave a natural iron content. Such a throughput of iron ensures that thecomposition of the liquid 34 will stay substantially constant. When suchan iron throughput exists, a tap 54 will generally be provided as a partof the reactor 14 for the removal of some of the liquid 34 and itseventual reprocessing in metallurgical refineries. In this manner, thecomposition of the liquid 34 can be kept substantially constant whilevarious metals and the like which may become concentrated therein can beconstantly stripped off and recovered via metallurgical processing.

Turning now to the energy extractor 16, it will be apparent that itreceives a hot gas via the takeoff pipe 52 and then directly makes useof the energy content of that hot gas to generate power. For example, ina first energy conversion stage 56, the hot gas from the oxidationchamber means 44 can generate electrical power efficiently via gasturbine operation, thermionic energy generation or other advancedtopping cycle energy generation. The hot gas is cooled somewhat by theenergy removed in the first stage 56, whereupon the somewhat cooled hotgas can pass to a second energy conversion stage 58 after air has beeninjected thereinto via an air injector 60 to combust a portion of thehot gas and reheat the hot gas to its original temperature or anotherdesired elevated temperature. In the second stage 58, electrical powercan be generated more efficiently at the original high temperature thanat the somewhat lowered temperature. From the second stage 58, the againsomewhat cooled gas can pass on to a third energy conversion stage 62via an intermediate air injector gas burner 64 which will raise thetemperature of the gas again through chemical reaction wherebyadditional energy may be extracted efficiently in the third stage 62. Ifdesired, the hot gas from the third stage 62 can pass through a heatexchanger 65 wherein the heat thereof is used to super heat steamconducted to an electric power plant or to heat feed water and/or air,with the feed water being used for any desired process and the air beingused, for example, as the air injected via the plurality of conduits 48into the oxidation chamber means 44.

Such staged combustion by air injection allows the hot gas to bemaintained quasi-isothermally throughout the system at the highesttemperature permitted by the energy conversion cycles, and by the limitimposed by the formation of nitrogen oxide pollutants in the exhaust,thereby allowing maximum efficiency and minimum size and cost of theenergy conversion system. Use of air injection into the hot fuel gas, ascompared with the conventional injection of fuel into a hot oxidizinggas, permits maintaining a highly reducing atmosphere throughout most ofthe energy conversion process. This greatly reduces the quantity ofnitrogen oxides formed at a given gas temperature and permits the use ofsuperior high temperature materials which cannot be used in an oxidizingatmosphere. It should be recognized that the hot off gas from thetakeoff pipe 52 (or its equivalent in other embodiments of the presentinvention) is used substantially better directly in a staged combustionprocess. The ratio of the heating value H_(R) of hot off gas to theheating value, H_(O) of gas at the same temperature obtained by burningcolder off gas is ##EQU1## where C is the specific heat of the gases, Qis their heat of combustion per pound and dT is the difference betweenoff gas temperature of the two different gasifiers. The first bracketedterm arises from the additional sensible heat in the hotter off gas. Thesecond bracketed term arises from the additional volume of nitrogenmixed with the colder gas during its combustion with air to the highertemperature. What results then is a staged combustion-energy abstractionapparatus referred to generally as an energy extractor 16, which energyextractor is operated directly by reactor 14 wherein a liquid 34dissolves carbon introduced from the digestor 12 and reacts that carbonwith an oxidizing means introduced into the oxidation chamber means 44to produce a hot gas, generally a hot fuel gas.

Since the feed 18 introduced into the digestor 12 and eventuallyintroduced in the form of the mass 24 into the reactor 14 will generallycontain a number of materials besides carbon, it is clear that animpurity slag layer 66 will be formed upon the surface 68 of the liquid34 and thereby be separated from the carbon and the valuable volatilechemicals. A slag tap 70 is thus preferably provided which serves as ameans for removing the impurity slag layer 66 formed in thecarbonization chamber 42. It is further noted that since the impurityslag layer 66 is maintained only within the carbonization chamber 42, asa result of the separation provided by the baffle means 40, there issubstantially no impurity slag layer within the oxidation chamber means44 and hence the oxidizing means, usually oxidation gas means,introduced into the oxidation chamber means 44 can be maintained inefficient close contact with the liquid 34 therein, leading to a highrate of oxygen reaction therewith in the liquid 34, and an absence offly ash in the hot gas exhaust evolved therefrom. The impurity slaglayer 66 as removed by the slag tap 70 can then be used to produceby-products such as bricks, insulation material and the like.

It will be noted that when an oxidizing gas is used with a high freeoxygen content, the reactor 14 may include means for skull coolingwhereby the liquid 34 is within a vessel made of solidified liquid 34.Thus, a plurality of skull cooling pipes 72 are provided within thewalls of the reactor 14. As cooling fluid (e.g., preheat oxidizing gas)is passed through the skull cooling pipes 72, the liquid 34 is cooled tobelow its melting point thereadjacent, thus forming a solid layer ofsolidified liquid 34 which serves as a non-corroding vessel for theliquid 34.

It will be noted that in the embodiment illustrated in FIG. 1, thedissolved carbon within the liquid 34 is circulated underneath thebaffle means 40 to the oxidation means chamber 44 and therein reactswith the iron oxide dissolved in the liquid 34 in said oxidation chambermeans 44 to form carbon monoxide which is quite insoluble in, forexample, molten liquid iron. The carbon monoxide thus forms a part ofthe hot gas which passes up the takeoff pipe 52. Another part of the hotgas which passes up the takeup pipe 52 is formed, for example, from theair which is injected thereinto. The oxygen of the air, as previouslymentioned, reacts with the iron to form iron oxide which is therebybound (chemically or physically) to the liquid 34. This oxygen laterbecomes carbon monoxide through reaction with the dissolved carbon asjust explained. The nitrogen, argon and the like in the air, however, isnot reactive under the conditions in the reactor 14 with the iron and issimply heated within the reactor 14 and forms a part of the first hotgas which passes up the takeoff pipe 52. Similarly, if steam is injectedalong with air, the oxygen is abstracted therefrom by the iron to formiron oxide with the concurrent production of hydrogen and with thehydrogen then forming a part of the gas which passes up the takeoff pipe52. Thus, that which is being converted to energy in the energyextractor 16 would comprise a mixture of nitrogen gas, hydrogen gas, andcarbon monoxide along with various impurity gases and perhaps somereaction gases of these.

SECOND EMBODIMENT OF THE INVENTION

Referring now particularly to FIG. 2, there is illustrated therein anembodiment of the present invention wherein the baffle means 40 definesin addition to the carbonization chamber 42 and the oxidation chambermeans 44, a leaching chamber 74 for sulfur removal. The baffle means 40serves to separate the leaching chamber 74 above the liquid level 36from the carbonization chamber 42 and the oxidation chamber means 44,but allows flow of the liquid 34, for example, under the influence ofmechanical stirrers 75, into the leaching chamber 74 from thecarburization chamber 42 and out of the leaching chamber 74 and into theoxidation chamber means 44. Thus, liquid 34 which has both carbon andsulfur dissolved therein can enter the leaching chamber 74 via entrancemeans 76 and can leave the leaching chamber 74 via exit means 78 and canenter the oxidation chamber means 44 via oxidation entrance means 79.

A high basicity mixture of metal oxides is maintained in the leachingchamber 74 as a leach slag 82 floating on the surface of the liquid 34.The leach slag 82 may include any of a number of alkali metal and/oralkaline earth oxides but will be spoken of as predominantly a calciumoxide slag for illustration purposes and because calcium oxide isreadily available and will work extremely well in the desulfurizationreaction, reacts with the dissolved sulfur to form calcium sulfide and agas comprising carbon monoxide. The purpose of the chemically non-activecomponents of the leach slag 82 is to lower its melting point andthereby allow the leach slag to be maintained in a molten state at thetemperature of the liquid 34 to ensure intimate and complete contactbetween the slag 82 and liquid 34. An example of a suitable slag if theliquid 34 is molten iron at 1500° C. would be the mixture 50% by weightCaO, 7% Al₂ O₃ and 43% SiO₂. The leach slag 82, which includes thecalcium sulfide formed within the leaching chamber 74, is substantiallyinsoluable in the liquid 34, which liquid 34 is generally molten ironand forms the separate molten leach slag layer 82 which floats upon theliquid 34 within the leaching chamber 74. A leach slag tap 84 isprovided for removal of the leach slag. The leach slag 82 may beconducted from the tap 84 to a conventional desulfurizer 86 wherein itscalcium sulfide content is reacted with steam and carbon dioxide to formsulfur which is removed and the regenerated leach slag 82 may berecycled into leaching chamber 74. Such regeneration and recycled isusable with all embodiments of the invention.

As illustrated in FIG. 3 and as is useful with all embodiments of theinvention, the leach slag 82 is preferably regenerated continuouslywithin the leaching chamber 74 by directing jets 88 of superheated steamonto its free surface. The steam reacts with the calcium sulfide in theleach slag 82 to form H₂ S, CO and a metal oxide, generally CaO. Theleach slag layer 82 prevents direct contact of the steam with the liquid34. The impingement of the steam jets upon the molten leach slag layer82 induces secondary flow (shown as circular arrow) which stirs thelayer causing efficient transfer of CaS from the slag-liquid interfaceto the steam-slag interface and the return of CaO.

A leaching chamber outlet pipe 92 serves for removal of the hydrogensulfide and carbon monoxide gases formed within the leaching chamber 74.This outlet pipe 92 can then be used as a feed to a converter whichconverts the H₂ S to elemental sulfur for example by the well-knownClaus process.

Adverting again primarily to FIG. 2, it is seen that the oxidationchamber means 44 can be divided in the embodiment illustrated in FIG. 2into a decarbonization chamber 94 and a first oxidation chamber 96. Thiscan be accomplished by extending the baffle means 40 to include meansfor separating the oxidation means 44 within the reactor 14 above theliquid level 36 from both the carbonization chamber 42 and the firstoxidation chamber 96, and, when such is provided, from the leachingchamber 74. With such a structure, the oxidizing gas means, for example,air, is introduced into the first oxidation chamber 96 via one or moreof the plurality of conduits 48 wherein it reacts with the molten liquid34 to provide oxygen bound therein, for example, iron oxide, and tofurther provide nitrogen as a hot gas which can exit therefrom as via afirst oxidation chamber outlet pipe 98. A first oxidationchamber-to-decarbonization chamber passage 100 is provided to allow thecirculation of oxygen rich liquid 34 into the decarbonization chamber94, wherein it reacts with carbon dissolved in the liquid 34 to formcarbon monoxide which then exits the decarbonization chamber 94 via adecarbonzation chamber outlet pipe 102. The concentration of oxygenintroduced into the decarbonization chamber 94 should be sufficient sothat when the liquid 34 is returned to the first oxidation chamber 96,the return liquid 34 is substantially free of carbon. Flow from thedecarbonization chamber 94 to the carbonization chamber 42, consistingof the combined flows through entrance means 76, contains sufficientexcess carbon to ensure that the liquid 34 which returns to thecarbonization chamber 42 to be substantially free of oxygen. Thisensures that a substantial amount of CO is not released in either thecarbonization or first oxidation chambers. The hot gas which passes outof the first oxidation chamber outlet pipe 98 is substantially nitrogen,and if steam is introduced, hydrogen. Thus, in the embodimentillustrated in the FIG. 2, the reactor 14 serves to provide at leastsomewhat purified gases, namely, carbon monoxide and nitrogen whichgases can have significant value in industrial processes and which gasescan have the energy therefrom extracted either in a single energyextractor 16 by combining the gases or separately in a plurality ofenergy extractors 16.

Referring again to FIG. 2, it is seen that oxidation chamber means 44can be divided into not only the decarbonization chamber 94 and thefirst oxidation chamber 96, but also into a second oxidation chamber 108into which steam is injected via conduits 109 and from which hydrogen isobtained in a fairly pure form from a second oxidation chamber outletpipe 110. In the embodiment of the invention illustrated in FIG. 3 it isclear that if the second oxidation chamber 108 is provided and utilizedthe product gases individually comprise nitrogen, hydrogen and carbonmonoxide. It is further clear that these gases can go to one or more ofthe energy extractors 16. The second oxidation chamber 108 is separatedby the baffle means 40 above the liquid level 36 from the leachingchamber 74, the decarbonization chamber 94, the carbonization chamber42, and the first oxidation chamber 96. Liquid flow communication of theliquid 34 is, however, allowed and in fact, is necessary for the overallrefining of the carbon.

THIRD EMBODIMENT OF THE INVENTION

Turning now to FIG. 4, there is illustrated therein an alternateembodiment of the digestor 12, wherein said digestor 12 forms a part ofthe reactor 14 and wherein the mass 24 of the feed 18 is fedhorizontally into the reactor 14 and more particularly, into thecarbonization chamber 42 thereof and generally onto the surface 68 ofthe liquid 34. In this embodiment of the invention, the first end 28 ofthe mass 24 progresses generally horizontally along the surface 68 ofthe liquid 34. The feed adding means in the embodiment of FIG. 4comprises force feeding means, for example, a conventional screwextruder 114 which rotates within a cylindrical tube 116 whereby thefeed 18 is fed to the extruder 114 and then force fed against the secondend 30 of the mass 24 as the extruder 114 rotates in the directionindicated in FIG. 4. A ram or other force feeding means can replace theextruder 114.

The takeoff means 32 in the embodiment of FIG. 4 comprise a plurality ofopenings 118 above the mass 24 leading off from the carburizationchamber 42 with the openings 118 being spaced from one another along thelength of the mass 24. What results then is a substantially horizontaldistillation column for digestor 12. For example, the leftwardmost ofthe openings 118 would extract the most volatile materials in the mass24, or produced by the decomposition, cracking and/or reforming thereofwhich occurs within the carbonization chamber 42. The rightwardmost ofthe openings 118 would take off only the least volatile of the fractionsproduced within the carbonization chamber 42. It is clear that highvolatility fractions produced towards the left end (the second end 30)of the mass 24 can rise completely through the low temperature upperportions of the left end of the mass 24 without condensing therein andexit via the leftwardmost of the openings 118. The low volatilityfractions produced toward the left end of the mass 24 will condense inthe upper portions and not be released until they are carried within themass 24 to the high temperature right end of the mass 24 in thecarbonization chamber 42 where they exit via the rightwardmost of theopenings 118.

As will be noted by reference to FIG. 4, the embodiment illustratedtherein includes a leaching chamber 74 as in either of the embodimentsshown in FIGS. 2 and 3. The embodiment of FIG. 4 further includesoxidation chamber means 44 which if desired, may take the configurationshown in FIG. 2. Hot fuel gas produced in the oxidation chamber means 44exits therefrom via the outlet pipe 52 and can proceed to the energyextractor 16. Steam or iron ore can be fed via the conduits 109 to thesecond oxidation chamber 108. Circulation of the liquid 34 isaccomplished by introducing some air via conduits 119 to the reactor 14below the liquid level 36.

The embodiment of FIG. 4 has one very particular distinct advantage overthe embodiment of FIG. 1 wherein a generally vertical digestor isutilized. This advantage results since much of the coal available in theUnited States is of a nature whereby it will swell and cakesignificantly on heating thereof. Thus, when one uses a verticaldigestor 12 a possibility of a problem of clogging exists towards thebottom end 26 thereof generally restricting its use to low-swellingcoals. In the embodiment of FIG. 4 the feed is horizontal and the mass24 does not become heated at all until it has been inserted into thecarbonization chamber 42 of the reactor 14 where it is an unconfinedfreely floating mass. Thus, expansion or caking of the feed 18 due toheating thereof cannot cause clogging.

FOURTH EMBODIMENT OF THE INVENTION

Another preferred embodiment of the present invention, which embodimentis useful with any of the previously described embodiments, is fullyillustrated in FIG. 5. In the embodiment shown in FIG. 5, the oxidationchamber means 44 includes means for preventing outflow of the carbonmonoxide produced therein unless the pressure thereof reaches a backpressure value. In the particular embodiment illustrated, the meanscomprises conventional flow regulator valve means 120 but in use suchback pressure value may comprise turbine or process inlet pressure. Theoxidation chamber means 44 is separated from the carbonization chamber42 by baffle means 40 or the equivalent, which in this embodimentcomprise simple pipes 122 or the like and the oxidation chamber means 44is pressurized by a head of the liquid 34 which is equal to thepredetermined value set in the flow regulator valve means 120 or thelike. In this manner, the head of the liquid 34 is used to pressurize,for example, the carbon monoxide and nitrogen, produced in the oxidationchamber means 44. This permits injecting the fuel mass 24 and operatingthe carbonization and other chambers at atmospheric pressure withoutpressure locks, while generating pressurized hot fuel gas in theoxidation chamber for use in a gas turbine engine or the like. Thus, inthe apparatus illustrated in FIG. 5, the liquid level comprises a firstliquid level 124 in the carbonization chamber 42 and a second liquidlevel 126 in the oxidation chamber means 44. Further, the difference inheight between the first liquid level 124 and the second liquid level126 comprises the hydraulic pressure head of the liquid 34 which isgenerally equal to the predetermined back pressure value of the carbonmonoxide, etc., within the oxidation chamber means 44 as set by thepressure regulator valve means 120 or the like.

It is clear that instead of or in addition to pressurizing the carbonmonoxide, etc., formed in the oxidation chamber means 44, one canlikewise or instead pressurize hot gases formed in other chambers in asimilar manner.

FIFTH EMBODIMENT OF THE INVENTION

Adverting to FIG. 6, there is illustrated an alternate embodiment toFIG. 5 for obtaining a pressurized gas product. In the embodiment ofFIG. 6 both the mass 24 and the oxygen containing gas introduced to thefirst oxidation chamber 96 are at atmospheric pressure. Thecarbonization chamber 94 is pressurized to produce carbon monoxide gasat the pressure of the head of the liquid 34 as set by the flowregulator valve means 120. The baffle means 40 is replaced in thisembodiment by the equivalent pipes 128, 130, 132 and 134. Circulation bynatural convection is indicated by arrows.

SIXTH EMBODIMENT OF THE INVENTION

FIG. 7 illustrates an embodiment of the present invention wherein arotary stirrer 136 is within the mass 24 and serves to rotate the mass24 thus setting up the necessary circulation within the reactor 14. Asin the embodiment of FIG. 4 the digestor 12 is part of the reactor 14.Feed 18 enters the reactor 14 by gravity flow about the stirrer 136. Theapparatus has the usual (to the invention) oxidation chamber means 44and carbonization chamber means 42. In the particular embodimentillustrated in FIG. 7 a leaching chamber 74 is provided of the type ofthe leaching chamber 74 of FIG. 3.

SEVENTH EMBODIMENT OF THE INVENTION

FIG. 8 illustrates an apparatus in accordance with the present inventionwhich utilizes physical separation of off gas. In this embodiment thefirst oxidation chamber 96 is narrow whereby residence time of theliquid 34 in the chamber is very short so that the carbon-oxygenreaction and resulting gas evolution does not go appreciably towardcompletion therein. This reaction then goes to completion in thedecarbonization chamber 94 whereat carbon monoxide is evolved. Thisembodiment would preferably utilize a leaching chamber 74 of the typeillustrated in FIG. 3.

PROCESS

While the processes by which the apparatus of the present inventionoperate should be generally apparent from the preceeding description ofthe apparatus and the interaction of the parts thereof, a brief summaryof the processes, per se, may be useful in further understandingthereof.

In one sense the process comprises introducing the feed 18 into thecarbonization chamber 42 of the reactor 14 and into contact, at atemperature above the carbonization temperature of the feed 18, with theliquid 34 which is a solvent for carbon and which fills the reactor 14up to the liquid level 36 therein. There is also introduced into theoxidation chamber means 44 in the reactor 14 (the oxidation chambermeans 44 being separated from the carbonization chamber 42 above liquidlevel 36 and flow of the liquid 34 being allowed between the oxidationchamber means 44 and the carbonization chamber 42) oxidizing meanshaving an oxygen content and being overall exothermically reactive withthe liquid 34 to elevate the temperature of the liquid 34 towards theaforementioned temperature above the carbonization temperature of thefeed 18. The term "overall exothermically reactive" means that theoverall reactions occurring in the entire process, including energyavailable from all products, can result in the net production of heat.The oxidizing means may be introduced at a velocity and in a directionwhich causes flow of the liquid 34 between the oxidation chamber means44 and the carbonization chamber 42, mechanical stirring means may beutilized, some oxygen may be introduced below the liquid level orcombinations of any of the above may be utilized to assure proper liquidflow. Finally, there is conducted away from the oxidation chamber means44 a hot gas formed therein by reaction of the oxygen content of theoxidizing means. Most generally, this reaction will be between theoxidizing means and the liquid 34, generally iron, but, for example, inthe embodiment shown in FIG. 1 wherein the oxidizing chamber meanscomprises a single chamber, this hot gas will also include thereincarbon monoxide, some of which may be formed by direct reaction of airwith carbon at the surface 68 of the liquid 34, along with nitrogen andpossibly hydrogen if steam is part of the oxidizing gas means.

The use of multiple chambers with resulting separation of gases alsofalls within the scope of certain embodiments of the present invention.Steam and/or iron ore (oxide) may be introduced in some of said multiplechambers as an oxidizing agent. The impurity layer 66 and the valuablevolatile components which form in the carbonization chamber 42 aregenerally removed separately therefrom.

In many of the embodiments shown, there is also formed within thereactor 14, a leaching chamber 74 and a metal oxide leach slag whichreacts with the sulfur in the liquid 34 and retains it as a sulfide,which sulfur extracting and retaining leach slag is substantiallyinsoluble in the liquid 34 and of a different (lower) density than theliquid 34, whereby the leach slag remains separated into a layer 82. Offgas formed within the leaching chamber will be conducted therefrom,which off gas will comprise carbon monoxide. Finally, the leach slaglayer 82 formed in the leaching chamber 74 will be removed therefrom. Asan added step, the removed leach slag may be reacted with carbon dioxideto produce elemental sulfur and recyclable metal oxide or hydroxide slagwhich may be recycled into the leaching chamber 74. Alternatively, theleach slag may be desulfurized continuously by reacting it in situ withsteam and forming H₂ S which is removed with the off gas from theleaching chamber.

The above description of the preferred embodiments of the inventionshould not be considered as limiting the invention since a number ofequivalent structures may be utilized in a like manner to accomplish alike result. Further, while the invention has generally been describedwith the preferred embodiment wherein the liquid 34 comprises iron, itshould be noted that the liquid 34 can likewise comprises any of anumber of other metals or alloys, or of molten salts, for example,molten calcium carbonate or mixtures of molten calcium carbonate withother molten salts. Yet further, while air has generally been used byway of example as the oxidizing gas means or at least a portion thereof,it should be realized that any oxygen containing gas can be so used.Further, any gas which will react with, for example, molten iron toproduce dissolved iron oxide and at the same time produce heat mayclearly be substituted for the air. Still further, iron oxide, e.g.,iron ore may serve as a portion of the oxygen source whereby iron is aproduct of the process.

EXAMPLE

The purpose of this example was to bring together principle elements ofthe process to demonstrate its actual operation and basic conceptualfeasibility.

The reactor vessel was a conventional 300 kW, 1400 pound capacity,Inductotherm induction furnace set up generally in accordance with thereactor 14 of FIG. 1. The 16 inch diameter by 22 inch deep crucible wascovered by a 2 inch thick lid of Fiberfrax "Hot Board". A two andone-half inch wide by nine inch partition of high-alumina refractorybrick (3000° F. service temperature) was cemented diametrically acrossthe crucible immediately below the lid. The joints between the lid andthe partition and between the lid and the crucible were made gas tightby interposed layers of Fiberfrax refractory felt. The crucible wascharged with molten iron (mild steel) until surface level was about oneand one-half inches above the bottom of the partition, and thetemperature was maintained near 2850° F. by induction heating.

A high-volatile 182 " mesh bituminous coal was charged into thepyrolysis (carbonization) chamber 42 through the coal inlet port in thelid until coal flow stopped. The coal was maintained continuously atthis level by adding coal to the inlet as coal was consumed in thepyrolysis (carbonization) chamber. When the first coal was injected,dense white smoke with a sulfurous odor evolved from the char gas outletwhich condensed partially as tar around the edge of the outlet andburned with a sooty flame. Also, at first, the rate of dissolution ofcoal in the iron was relatively slow (only about five pounds in thefirst hour). This rate continuously increased with time, however (toabout ten pounds per hour). It appeared that the low rate was due to asolid iron layer forming at the coal-iron interface due to the heatremoved by the cracking of the coal. As the carbon content of the ironpool increased, and its melting point decreased, this problem wasalleviated. This problem can be avoided by starting with high-carboniron. After about one-half hour, the smoke and tar gradually disappearedfrom the char gas and it burned thereafter with a steady incandescent,smokeless and odorless flame resembling that of methane.

After about one hour of operation of the pyrolysis (carbonization)chamber, when the iron carbon content reached about 1/2 weight percent,air flow was initiated into the inlet of the oxidation chamber 44. Forrelatively slow air injection rates (less than 1 scf/min) an odorlessoff gas, which burned cleanly with a clear blue-white flame, was evolvedfrom the high alumina off gas outlet stack. At high injection rates theevolved gas would not burn. Apparently, here also, the net endothermicreaction of the nonpreheated air with the carbon in the iron caused asolid iron crust to form beneath the jet, inhibiting the reaction. Thislimitation can also be avoided by starting with a high carbon contentiron, as well as providing an adequate degree of air preheat.

After a total of about three hours operation, when the carbon contentreached about 1 percent, oxygen flow at about 3 scf/min was initiatedinto the oxidation chamber inlet. The off gas flame was similar incharacter to the air-blown off gas flame (but much larger) and burnedsteadily. Because the net reaction was exothermic the electrical powerto the induction furnace was turned off at this time. When the oxygenflow was increased to about five scf/min, the flame increasedproportionately in size, but the off gas temperature exceeded thedestruction temperature of the lid, terminating the test.

In summary, the following elements were operated together as a singleseries coupled system:

1. A multi-chamber molten-iron coal gasifier in a single reactor vessel.p1 2. Forced pyrolysis and dissolution of coal in molten iron in one ofthe chambers.

3. Gasification of the dissolved carbon in another chamber by injectionof air or oxygen from above the surface of the molten iron pool.

4. Separation of the high btu char gas from the low btu off gas.

5. Isolation of the coal ash from the off gas by flotation as slag onmolten iron in the pyrolysis chamber.

6. Horizontal feed of a pyrolyzing and dissolving coal layer byflotation of the layer on molten iron.

7. Isolation of other impurities (e.g., sulfur) from the off gas bytheir solution and retention in the molten iron solvent.

While the invention has been described in connection with specificembodiments thereof, it will be understood that it is capable of furthermodification, and this application is intended to cover any variations,uses or adaptations of the invention following, in general, theprinciples of the invention and including such departures from thepresent disclosure as come within known or customary practice in the artto which the invention pertains and as may be applied to the essentialfeatures hereinbefore set forth, and as fall within the scope of theinvention and the limits of the appended claims.

That which is claimed is:
 1. Apparatus for converting a feed whichincludes a sulfur component and which yields carbon on being heatedabove a carbonization temperature thereof and which is solid at ambienttemperature into a hot gas, comprising:a reactor; a liquid solvent forcarbon which fills said reactor up to a liquid level therein below a topthereof; partition means, separating said reactor above said liquidlevel into a carbonization chamber and oxidation chamber means, saidpartition means terminating below said liquid level and above a bottomof said reactor to allow flow of liquid between said carbonizationchamber and said oxidation chamber means, said partition means furtherdefining a leaching chamber within said reactor separated above saidliquid level from said carbonization chamber and said oxidation chambermeans but allowing flow of liquid thereinto and thereoutof; means forintroducing a feed which yields carbon on being heated above acarbonization temperature thereof and which is solid at ambienttemperature into said carbonization chamber; means for introducingoxidizing means having an oxygen content into said oxidation chambermeans to produce oxygen bound in said liquid solvent; means for causingflow of said liquid between said carbonization chamber and saidoxidation chamber means; means for introducing a metal oxide, said metalforming a sulfide which is insoluble in said liquid and of a differentdensity therefrom whereby said metal sulfide when formed separates intoa sulfide layer, into said leaching chamber; means for conducting offgas formed by reaction of said metal oxide with sulfur and carbondissolved in said liquid in said leaching chamber away therefrom; meansfor removing said sulfide layer from said leaching chamber; and meansfor conducting away from said oxidation chamber means a first hot gasformed therein.
 2. Apparatus as in claim 1, wherein said liquid solventcomprises molten iron at a temperature within a range from about 1100°C. to about 1700° C.
 3. Apparatus as in claim 2, furthercomprising:means for reacting said removed sulfide with carbon dioxideto produce elemental sulfur and recyclable metal oxide.
 4. Apparatus asin claim 3, including:means for transferring said recyclable metal oxideto said metal oxide introducing means.
 5. Apparatus for converting afeed which yields carbon on being heated above a carbonizationtemperature thereof and which is solid at ambient temperature into a hotgas, comprising:a reactor; a liquid solvent for carbon which fills saidreactor up to a liquid level therein below a top thereof; partitionmeans, separating said reactor above said liquid level into acarbonization chamber and oxidation chamber means, said partition meansterminating below said liquid level and above a bottom of said reactorto allow flow of liquid between said carbonization chamber and saidoxidation chamber means; means for introducing a feed which yieldscarbon on being heated above a carbonization temperature thereof andwhich is solid at ambient temperature into said carbonization chamber,said feed introducing means comprising means for contacting a first endof a mass of said feed extending generally linearly into saidcarbonization chamber with said liquid; and means for progressivelyadding said feed to a second end of said mass to maintain the extensionthereof into said carbonization chamber substantially constant andcreate a temperature gradient therealong; a plurality of volatilefraction takeoff means in flow communication with said mass along thelength thereof for selectively removing fractions of differingvolatilities therefrom; means for introducing oxidizing means having anoxygen content into said oxidation chamber means to produce oxygen boundin said liquid solvent; means for causing flow of said liquid betweensaid carbonization chamber and said oxidation chamber means; and meansfor conducting away from said oxidation chamber means a first hot gasformed therein.
 6. Apparatus as in claim 5, wherein said first end feedcontacting means comprises a generally vertical digester through whichsaid feed progresses downwardly under the influence of gravity and saidfirst end of said feed comprises a bottom end thereof, said feed addingmeans comprises means for adding feed to a top portion of said digesterand said fraction takeoff means comprises a plurality of verticallyseparated openings through an external wall of said digester. 7.Apparatus as in claim 6, wherein said liquid solvent comprises molteniron at a temperature which falls within a range from about 1100° C. toabout 1700° C.
 8. Apparatus as in claim 7, including:means for removinga slag layer formed in said carbonization chamber.
 9. Apparatus as inclaim 8, wherein said feed includes a sulfur component, said partitionmeans further defines a leaching chamber within said reactor separatedabove said liquid level from said carbonization chamber and saidoxidation chamber means but allowing flow of liquid thereinto andthereoutof and further comprising:means for introducing a metal oxide,said metal forming a sulfide which is insoluble in said liquid and of adifferent density therefrom whereby said metal sulfide when formedseparates into a sulfide layer, into said leaching chamber; means forconducting off gas formed by reaction of said metal oxide with sulfideand carbon dissolved in said liquid in said leaching chamber awaytherefrom; and means for removing said sulfide layer from said leachingchamber.
 10. Apparatus as in claim 9, further comprising:means forreacting said removed sulfide with carbon dioxide to produce elementalsulfur and recyclable metal oxide or hydroxide.
 11. Apparatus as inclaim 10, including:means for transferring said recyclable metal oxideor hydroxide to said metal oxide or hydroxide introducing means. 12.Apparatus as in claim 11, wherein said oxidation chamber means comprisesa decarbonization chamber and a first oxidizing chamber within saidreactor defined by said partition means, said decarbonization chamber isseparated above said liquid level from said carbonization and said firstoxidation chambers but said partition means allows flow of liquid intosaid decarbonization chamber with carbon dissolved therein from saidcarbonization chamber and of liquid with oxygen bound therein from saidfirst oxidation chamber and flow of liquid from said decarbonizationchamber substantially free of oxygen bound therein to saiddecarbonization chamber and of liquid therefrom having oxygen boundtherein to said first oxidation chamber and further comprising:means forconducting a second hot gas away from said decarbonization chamber. 13.Apparatus as in claim 12, wherein said oxidation chamber means furthercomprises a second oxidation chamber separated above said liquid levelfrom said decarbonization and first oxidation chambers but in liquidflow communication therewith, said oxidizing means comprises a firstoxidizing gas comprising air introduced into said first oxidationchamber and a second oxidizing gas comprising steam introduced into saidsecond oxidization chamber, said first hot gas comprises a firstseparate portion comprising nitrogen produced in said first oxidationchamber and a second separate portion comprising hydrogen produced insaid second oxidation chamber, and said second hot gas comprises carbonmonoxide.
 14. Apparatus as in claim 5, wherein said first end feedcontacting means comprises means for feeding said mass generallyhorizontally into said carbonization chamber generally onto a surface ofsaid liquid and said first end of said mass progresses generallyhorizontally along said surface, said feed adding means comprises meansfor force feeding said feed against said second end of said mass andsaid fraction takeoff means comprise a plurality of openings above saidmass and spaced from one another along the length thereof.
 15. Apparatusas in claim 14, including:means for removing a slag layer formed in saidcarbonization chamber.
 16. Apparatus as in claim 15, wherein said feedincludes a sulfur component, said partition means further defines aleaching chamber within said reactor separated above said liquid levelfrom said carbonization chamber and said oxidation chamber means butallowing flow of liquid thereinto and thereoutof and furthercomprising:means for introducing a metal oxide, said metal forming asulfide which is insoluble in said liquid and of a different densitytherefrom whereby said metal sulfide when formed separates into asulfide layer, into said leaching chamber; means for conducting off gasformed by reaction of said metal oxide with sulfur and carbon dissolvedin said liquid in said leaching chamber away therefrom; and means forremoving said sulfide layer from said leaching chamber.
 17. Apparatus asin claim 16, further comprising:means for reacting said removed sulfidewith carbon dioxide to produce elemental sulfur and recyclable metaloxide.
 18. Apparatus as in claim 17, including:means for transferringsaid recyclable metal oxide to said metal oxide introducing means. 19.Apparatus as in claim 18, wherein said oxidation chamber means comprisesa decarbonization chamber and a first oxidizing chamber within saidreactor defined by said partition means, said decarbonization chamber isseparated above said liquid level from said carbonization chamber andsaid first oxidation chambers but said partition means allows flow ofliquid into said decarbonization chamber with carbon dissolved thereinfrom said carbonization chamber and of liquid with oxygen bound thereinfrom said first oxidation chamber and flow of liquid from saiddecarbonization chamber substantially free of oxygen bound therein tosaid carbonization chamber and further comprising:means for conducting asecond hot gas away from said decarbonization chamber.
 20. Apparatus forconverting a feed which yields carbon on being heated above acarbonization temperature thereof and which is solid at ambienttemperature into a hot gas, comprising:a reactor; a liquid solvent forcarbon which fills said reactor up to a liquid level therein below a topthereof; partition means, separating said reactor above said liquidlevel into a carbonization chamber and oxidation chamber means, saidpartition means terminating below said liquid level and above a bottomof said reactor to allow a flow of liquid between said carbonizationchamber and said oxidation chamber means; means for introducing a feedwhich yields carbon on being heated above a carbonization temperaturethereof and which is solid at ambient temperature into saidcarbonization chamber; means for introducing oxidizing means having anoxygen content into said oxidation chamber means to produce oxygen boundin said liquid solvent; means for causing flow of said liquid betweensaid carbonization chamber and said oxidation chamber means; means forconducting away from said oxidation chamber means a first hot gas formedtherein; and back pressure creating means in said hot gas conductingmeans to prevent flow of said hot gas therethrough unless the pressurethereof reaches a required value; and wherein said liquid levelcomprises a first liquid level in said carbonization chamber and asecond liquid level in said oxidation chamber means and the differencein height between said first and second liquid levels comprises ahydraulic pressure head of said liquid generally equal to said requiredhot gas pressure value.
 21. Apparatus as in claim 20, including meansfor abstracting energy in usable form from said hot gas after it hasbeen compressed to said predetermined pressure value.
 22. Apparatus asin claim 21, wherein said liquid solvent comprises molten iron at atemperature which falls within a range from about 1100° C. to about1700° C.
 23. Apparatus as in claim 22, wherein said energy abstractingmeans comprises gas turbine means.
 24. Apparatus for converting a feedwhich yields carbon on being heated above a carbonization temperaturethereof and which is solid at ambient temperature into a hot gas,comprising:a reactor; a liquid solvent for carbon which fills saidreactor up to a liquid level therein below a top thereof; partitionmeans, separating said reactor above said liquid level into acarbonization chamber and oxidation chamber means, said partition meansterminating below said liquid level and above a bottom of said reactorto allow flow of liquid between said carbonization chamber and saidoxidation chamber means; means for introducing a feed which yieldscarbon on being heated above a carbonization temperature thereof andwhich is solid at ambient temperature into said carbonization chamber,said feed introducing means comprising means for contacting a generallycircular mass of said feed extending into said carbonization chamberwith said liquid; and means for progressively adding said feed to acentral portion of said mass to maintain the extention thereof into saidcarbonization chamber substantially constant and create a temperaturegradient from said central portion to a peripheral portion of said mass;means for causing flow of said liquid between said carbonization chamberand said oxidation chamber means; a plurality of volatile fractiontakeoff means in flow communication with said carbonization chamberextending radially along said mass for selectively removing fractions ofdiffering volatilities therefrom; and means for conducting away fromsaid oxidation chamber means a first hot gas formed therein. 25.Apparatus as in claim 24, including:stirrer means engaged in saidcentral portion of said mass for rotating said mass and therebyimproving dissolution of said mass and creating fluid flow within saidliquid.
 26. Apparatus as in claim 25, including means for abstractingenergy in useable form from said hot gas.
 27. Apparatus as in claim 26,wherein said liquid solvent comprises molten iron at a temperature whichfalls within a range from about 1100° C. to about 1700° C.
 28. Apparatusas in claim 27, wherein said energy abstracting means comprises gasturbine means.
 29. Apparatus as in claim 28, wherein said gas turbinemeans includes a plurality of combustion stages which sequentiallycombust portions of said second gas to maintain the temperature of saidsecond gas within a temperature range corresponding generally to maximumefficiency of said gas turbine means.